1. Field of the Invention
The present invention relates to a circuit board connector terminal (referred to terminal hereafter) to be connected electrically with conductive portions of walls in a through-hole by depressing the terminal into the through-hole of a print circuit board or a circuit board such as a bus bar.
2. Description of the Related Art
A conventional terminal 50 includes a narrow lead 51 at a tip end, a wide insertion portion 52 at a middle point to be force fitted into a through-hole 56, and an electric contact portion 54 at the other end, as shown in FIG. 8A. See, for example, JP,H08-69828,A (page 3, FIG. 5). A thin portion 52a is formed in a middle of the width of the insertion portion 52 and both sides thereof are resiliently deformed in the width direction. The width of the through-hole 56 is smaller than that of the insertion portion 52. Then, when the insertion portion 52 enters into the through-hole 56, it deforms inwardly from both sides. The terminal 50 is fixed to a circuit board 55 when an end 53a of a shoulder 53 contacts to an upper face 55a of the circuit board 55.
Another conventional terminal connected with a conductive portion electrically in a through-hole is disclosed in JP,H05-114427,A (FIG. 2). This terminal deforms elastically and can enter into a small through-hole.
However, the above conventional terminals 50 leave several problems to be solved. The insertion portion 52 supports the terminal 50 and also is connected electrically to the conductive portion in the through-hole 56. Then, if a large supporting force (locking force) is applied to the terminal 50 not to pull out of the through-hole 56, a large insertion force is necessary to depress the terminal 50. If the large insertion force deforms the terminal 50, the electrical contact is lost and the terminal 50 is not reused.
In order to reduce the insertion force of the terminal 50, a slit is formed in the middle portion of the width of the insertion portion 52 to make both sides of the slit bend easily. However, in this case, the supporting force becomes weak and the terminal 50 pulls out of the through-hole 56.
It is intended that the both sides of the insertion portion 52 are in contact with walls of the through-hole 56. However, a front and back face of the insertion portion 52 happen to be not in contact or incomplete contact with the walls of the through-hole 56 and the contact area between the circuit board 55 and the terminal 50 becomes small. If there is a space between the front and back faces of the terminal 50, and the walls of the through-hole 56, the terminal 50 falls over or bend when it is force fitted into the through-hole.